scholarly journals Thermostable cellobiohydrolase from the thermophilic eubacterium Thermotoga sp. strain FjSS3-B.1. Purification and properties

1991 ◽  
Vol 277 (3) ◽  
pp. 887-890 ◽  
Author(s):  
L D Ruttersmith ◽  
R M Daniel

Exo-1,4-beta-cellobiohydrolase (EC 3.2.1.91) was isolated from the culture supernatant of Thermotoga sp. strain FjSS3-B.1, an extremely thermophilic eubacterium that grows optimally at 80 degrees C. The enzyme was purified to homogeneity as determined by SDS/PAGE and has an Mr of 36,000. The enzyme is the most thermostable cellulase reported to date, with a half-life at 108 degrees C of 70 min in buffer. In a 40 min assay, maximal activity was recorded at 105 degrees C. Cellobiohydrolase from strain FjSS3-B.1 is active against amorphous cellulose and CM-cellulose but only effects limited hydrolysis of filter paper or Sigmacell 20. The only product identified by h.p.l.c. is the disaccharide cellobiose. The enzyme has a pH optimum around neutral and is stabilized by the presence of 0.8 M-NaCl.

1996 ◽  
Vol 316 (3) ◽  
pp. 841-846 ◽  
Author(s):  
Stuart M. PITSON ◽  
Robert J. SEVIOUR ◽  
Barbara M. McDOUGALL ◽  
Bruce A. STONE ◽  
Maruse SADEK

An endo-(1 → 6)-β-glucanase has been isolated from the culture filtrates of the filamentous fungus Acremonium persicinum and purified by (NH4)2SO4 precipitation followed by anion-exchange and gel-filtration chromatography. SDS/PAGE of the purified enzyme gave a single band with an apparent molecular mass of 42.7 kDa. The enzyme is a non-glycosylated, monomeric protein with a pI of 4.9 and pH optimum of 5.0. It hydrolysed (1 → 6)-β-glucans (pustulan and lutean), initially yielding a series of (1 → 6)-β-linked oligoglucosides, consistent with endo-hydrolytic action. Final hydrolysis products from these substrates were gentiobiose and gentiotriose, with all products released as β-anomers, indicating that the enzyme acts with retention of configuration. The purified enzyme also hydrolysed Eisenia bicyclis laminarin, liberating glucose, gentiobiose, and a range of larger oligoglucosides, through the apparent hydrolysis of (1 → 6)-β- and some (1 → 3)-β-linkages in this substrate. Km values for pustulan, lutean and laminarin were 1.28, 1.38, and 1.67 mg/ml respectively. The enzyme was inhibited by N-acetylimidazole, N-bromosuccinimide, dicyclohexylcarbodi-imide, Woodward's Regent K, 2-hydroxy-5-nitrobenzyl bromide, KMnO4 and some metal ions, whereas D-glucono-1,5-lactone and EDTA had no effect.


1988 ◽  
Vol 255 (3) ◽  
pp. 833-841 ◽  
Author(s):  
J D Erfle ◽  
R M Teather ◽  
P J Wood ◽  
J E Irvin

A 1,3-1,4-beta-D-glucanase (lichenase, 1,3-1,4-beta-D-glucan 4-glucanohydrolase, EC 3.2.1.73) from Bacteroides succinogenes cloned in Escherichia coli was purified 600-fold by chromatography on Q-Sepharose and hydroxyapatite. The cloned enzyme hydrolysed lichenin and oat beta-D-glucan but not starch, CM(carboxymethyl)-cellulose, CM-pachyman, laminarin or xylan. The enzyme had a broad pH optimum with maximum activity at approx. pH 6.0 and a temperature optimum of 50 degrees C. The pH of elution from a chromatofocusing column for the cloned enzyme was 4.7 (purified) and 4.9 (crude) compared with 4.8 for the mixed-linkage beta-D-glucanase activity in B. succinogenes. The Mr of the cloned enzyme was estimated to be 37,200 by gel filtration and 35,200 by electrophoresis. The Km values estimated for lichenin and oat beta-D-glucan were 0.35 and 0.71 mg/ml respectively. The major hydrolytic products with lichenin as substrate were a trisaccharide (82%) and a pentasaccharide (9.5%). Hydrolysis of oat beta-D-glucan yielded a trisaccharide (63.5%) and a tetrasaccharide (29.6%) as the major products. The chromatographic patterns of the products from the cloned enzyme appear to be similar to those reported for the mixed-linkage beta-D-glucanase isolated from Bacillus subtilis. The data presented illustrate the similarity in properties of the cloned mixed-linkage enzyme and the 1,3-1,4-beta-D-glucanase from B. subtilis and the similarity with the 1,4-beta-glucanase in B. succinogenes.


1993 ◽  
Vol 295 (1) ◽  
pp. 149-154 ◽  
Author(s):  
D P Whitaker ◽  
M W Goosey

The enzyme arylamine N-acetyltransferase (ANAT) from the housefly (Musca domestica) has been purified. The M(r) of the purified enzyme was 27,600 +/- 1700 as estimated by gel filtration. SDS/PAGE yielded a value of 26,000 +/- 300, clearly indicating a monomeric structure. The purified enzyme had apparent Km values for acetyl-CoA and tyramine of 8.4 microM and 8.8 microM respectively, a pH optimum of 7.2 in 10 mM potassium phosphate buffer and an apparent pI of 5.8. ANAT activity showed a strong dependency on the presence of 2-mercaptoethanol during the purification stages. The enzyme could be completely inactivated by treatment with p-chloromercuribenzoate although the enzyme activity was protected by preincubation with acetyl-CoA. One or more cysteine residues are clearly required for catalytic activity, as demonstrated for the mammalian enzyme. In contrast, partial sequencing of the enzyme has yielded a number of peptide sequences, including the N-terminal sequence, which show no similarity with those reported for the mammalian and avian enzymes.


1969 ◽  
Vol 113 (4) ◽  
pp. 697-705 ◽  
Author(s):  
R. H. Quarles ◽  
R. M. C. Dawson

1. The hydrolysis of monolayers of phosphatidyl[Me−14C]choline at the air/water interface by phospholipase D (phosphatidylcholine phosphatidohydrolase) was investigated by a surface-radioactivity technique by using a flow counter. 2. Phosphatidylcholine of high specific radioactivity was prepared biosynthetically in good yield from [Me−14C]choline by using Saccharomyces cerevisiae. 3. At initial monolayer pressures between 12 and 25 dynes/cm. the hydrolysis occurred in two stages, an initial slow hydrolysis followed by a rapid hydrolysis. Below 3dynes/cm. and above 28dynes/cm. no enzymic hydrolysis of pure phosphatidylcholine monolayers could be detected. 4. The rapid hydrolysis was proportional to the enzyme concentration in the subphase, its pH optimum was 6·6, and 0·2mm-Ca2+ was required for maximal activity. 5. Hydrolysis of the film was accompanied by a pronounced fall in the surface pressure even though the phosphatidic acid formed did not leave the film. When the pressure fell to low values the hydrolysis ceased even if the film was only partially hydrolysed. 6. Above monolayer pressures of 28dynes/cm. enzymic hydrolysis could be initiated by inclusion of phosphatidic acid (and less effectively stearyl hydrogen sulphate) in the film, although the rates were not appreciably higher than those observed at 25dynes/cm. with a pure phosphatidylcholine film. 7. The initiation of the hydrolysis by phosphatidic acid was facilitated by the inclusion of high Ca2+ concentrations and certain carboxylic acid buffer anions in the subphase, although these did not activate by themselves. 8. The initiation of the hydrolysis at high pressures could not be related to any change in the surface potential brought about by the addition of the long-chain anions to the film, nor could it be ascribed to a surface dilution effect. 9. The results are discussed in relation to previous studies on the hydrolysis of phosphatidylcholine particles by the enzyme and also similar investigations on phosphatidylcholine monolayers with other phospholipases.


1994 ◽  
Vol 299 (3) ◽  
pp. 895-902 ◽  
Author(s):  
R M Jones ◽  
P M Jordan

Porphobilinogen deaminase (EC 4.3.1.8) has been purified to homogeneity (16,000-fold) from the plant Arabidopsis thaliana in yields of 8%. The deaminase is a monomer of M(r) 35,000, as shown by SDS/PAGE, and 31,000, using gel-filtration chromatography. The pure enzyme has a Vmax. of 4.5 mumol/h per mg and a Km of 17 +/- 4 microM. Determination of the pI and pH optimum revealed values of 5.2 and 8.0 respectively. The sequence of the N-terminus was found to be NH2-XVAVEQKTRTAI. The deaminase is heat-stable up to 70 degrees C and is inhibited by NH3 and hydroxylamine. The enzyme is inactivated by arginine-, histidine- and lysine-specific reagents. Incubation with the substrate analogue and suicide inhibitor, 2-bromoporphobilinogen, results in chain termination and in inactivation.


1991 ◽  
Vol 277 (2) ◽  
pp. 413-417 ◽  
Author(s):  
H D Simpson ◽  
U R Haufler ◽  
R M Daniel

Endo-1,4-beta-xylanase (EC 3.2.1.8) was isolated from the culture supernatant of Thermotoga sp. strain FjSS3-B.1, an extremely thermophilic anaerobic eubacterium which grows optimally at 80 degrees C. Activity was purified 165-fold by anion-exchange and hydroxyapatite chromatography. The enzyme has an Mr of 31,000 as determined by SDS/PAGE and 35,000 by analytical gel filtration. The optima for activity and stability for purified xylanase were between pH 5.0 and 5.5. At pH 5.5, which is the optimum pH for thermostability, t1/2 (95 degrees C) is 90 min. The thermostability was improved by immobilization of the xylanase on to porous glass beads; t1/2 (105 degrees C) is 10 min. Several additives, such as sorbitol and xylan, were also found to increase the thermostability. At 130 degrees C, the half-life of immobilized xylanase in the presence of 90% sorbitol was 1.3 min. At 130 degrees C in molten sorbitol half of the enzyme denatured rapidly, but the remainder appeared to have a half-life of about 60 min.


1974 ◽  
Vol 52 (10) ◽  
pp. 903-910 ◽  
Author(s):  
Robert E. Hoagland ◽  
George Graf

An amidohydrolase (EC 3.5.1.13) was isolated from the roots of soybean (Glycine max Merril, var. Hawkeye) seedlings and purified 130-fold over the crude extract with 30% recovery. The purification steps entailed ammonium sulfate precipitation, gel filtration, cellulose ion-exchange chromatography, and polyacrylamide gel electrophoresis. The specific activity of the purified enzyme for the hydrolysis of Nα-benzoyl-DL-arginine p-nitroanilide (BAPA) was 810 mU/mg. The Km of the enzyme for this substrate was 5.78 × 10−6 M. The enzyme possessed a broad substrate specificity and catalyzed the hydrolysis of BAPA, glycine p-nitroanilide, L-leucine p-nitroanilide, and L-lysine p-nitroanilide. Specificity studies with a series of aminoacyl β-naphthylamides revealed a high hydrolysis rate on Nα-benzoyl-L-arginine β-naphthylamide, and lower hydrolysis rates on several other aminoacyl-substituted β-naphthylamides. The enzyme also displayed dipeptide hydrolase activity on several dipeptide substrates. The enzyme had a pH optimum of 8.0 in 0.05 M phosphate buffer with Nα-benzoyl-DL-arginine p-nitroanilide as substrate. The temperature optimum was 50 °C. The apparent activation energy determined from an Arrhenius plot was 6.3 kcal/mol (26 400 J/mol). The molecular weight estimated by gel filtration was approximately 63 000. Mercury (II) ion, silver (I) ion, p-benzoquinone, p-chloromercuribenzoate, and N-ethylmaleimide were effective inhibitors of the enzyme.


1987 ◽  
Vol 245 (2) ◽  
pp. 515-524 ◽  
Author(s):  
A J Kenny ◽  
J Ingram

A second endopeptidase is present in the renal microvillar membrane of rats that can be distinguished from endopeptidase-24.11 by its insensitivity to inhibition by phosphoramidon. The purification of this enzyme, referred to as endopeptidase-2, is described. The enzyme was efficiently released from the membrane by treatment with papain. The subsequent four steps depended on ion-exchange and gel-filtration chromatography. These steps were monitored by the hydrolysis of various substrates: 125I-insulin B chain (the normal assay substrate), benzoyl-L-tyrosyl-p-aminobenzoate (Bz-Tyr-pAB), azocasein and benzyloxycarbonyl-L-phenylalanyl-L-arginine 7-amino-4-methylcoumarylamide (Z-Phe-Arg-NMec). All four assays revealed comparable stepwise increases in activity in the main stages of the purification, although it was apparent that the last-named fluorogenic assay depended on traces of aminopeptidase activity present in the preparation. The Km for 125I-insulin B chain was 16 microM and that for Bz-Tyr-pAB was 4.7 mM. Several experimental approaches confirmed that both peptides were hydrolysed by the same enzyme. The pH optimum was 7.3. Phosphate buffers were inhibitory and shifted the optimum to above pH 9. Zinc was detected in the purified enzyme; EDTA and 1,10-phenanthroline were strongly inhibitory. SDS/polyacrylamide-gel electrophoresis revealed polypeptides of equal staining intensity of Mr 80,000 and 74,000 in reducing conditions. In non-reducing conditions a single band of apparent Mr 220,000 was seen. Gel filtration yielded an Mr of 436,000. These results are consistent with an oligomeric structure in which the alpha and beta chains are linked by disulphide bridges. Endopeptidase-2 hydrolysed a number of neuropeptides. Enkephalins resisted attack, only the heptapeptide [Met]enkephalin-Arg6-Phe7 being susceptible to slow hydrolysis. Luliberin (luteinizing-hormone-releasing hormone) and bradykinin were rapidly hydrolysed. Neurotensin was shown to be slowly attacked at the Tyr3-Glu4 bond. Thus the specificity appears to be limited to the hydrolysis of bonds involving the carboxy group of aromatic residues, provided that this P1 residue is extended by additional residues, at least to the P3′ position. The relationship of this membrane metalloendopeptidase to mouse meprin and human ‘PABA peptidase’ is discussed.


2021 ◽  
Vol 85 (3) ◽  
pp. 600-610
Author(s):  
Akihiro Fujita ◽  
Akira Kawashima ◽  
Yuuki Mitsukawa ◽  
Noriaki Kitagawa ◽  
Hikaru Watanabe ◽  
...  

ABSTRACT Glucanotransferases that can synthesize cyclo-{→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→6)-α-d-Glcp-(1→} (CI4) from dextran were purified to homogeneity from the culture supernatant of Agreia sp. D1110 and Microbacterium trichothecenolyticum D2006. The molecular mass of both enzymes was estimated to be 86 kDa by SDS-PAGE. The glucanotransferase, named CI4-forming enzyme, from Agreia sp. exhibited the highest activity at pH 6.0 and 40 °C. The enzyme was stable on the pH range of 4.6-9.9 and up to 40 °C. On the other hand, the enzyme from M. trichothecenolyticum exhibited the highest activity at pH 5.7 and 40 °C. The enzyme was stable on the pH range of 5.0-6.9 and up to 35 °C. Both enzymes catalyzed 4 reactions, namely, intramolecular α-1,6-transglycosylation (cyclization), intermolecular α-1,6-transglycosylation, hydrolysis of CI4, and coupling reaction. Furthermore, the CI4-forming enzyme produced CI4 from α-1,6-linked glucan synthesized from starch by 6-α-glucosyltransferase. These findings will enable the production of CI4 from starch.


1992 ◽  
Vol 285 (1) ◽  
pp. 41-46 ◽  
Author(s):  
G O Gbenle ◽  
D M Dwyer

A surface membrane 3′-nucleotidase from Leishmania donovani promastigotes has been purified to SDS/PAGE homogeneity. The enzyme has apparent subunit molecular mass of 38 kDa, pI 5.8 and a broad pH optimum, 5.5-7.5. EDTA partially inhibited the enzyme activity, which was fully restored by Co2+; Mg2+, Ca2+ or Mn2+ had no effect on the activity. ZnCl2 or dithiothreitol at 1 mM was inhibitory at pH 7.5, but was without effect at pH 5.5, whereas at both pH values 5 mM of either compound inhibited the enzyme. The substrate-specificity of the purified enzyme is restricted to ribonucleoside 3′-phosphates. 3′-AMP and 3′-IMP are the best substrates, whereas ADP, ATP, 2′-deoxyadenosine 3′-phosphate and 5′-AMP are competitive inhibitors of the enzyme. The enzyme showed low latency in intact-cell preparations. The kinetic properties and the surface membrane localization of the enzyme suggest its implication in the formation of nucleosides from 3′-nucleotides of the parasite's host.


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